Novel mutations in arrhythmogenic right ventricular cardiomyopathy from Indian population

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive condition with right ventricular myocardium being replaced by fibro-fatty tissue. The spectrum of the expression may range from benign palpitations to the most malignant sudden death. Most of the mutations identified for the condition are localized in desmosomal proteins although three other nondesmosomal genes (cardiac ryanodine receptor-2, TGF-b3, and TMEM43) have also been implicated in ARVC. Both desmosomal and nondesmosomal genes were screened in a set of patients from local population.
Materials and Methods: A set of 34 patients from local population were included in this study. Diagnosis was based on the criteria proposed by task force of European Society of Cardiology/International Society and Federation of Cardiology. Polymerase chain reaction-based single-strand conformation polymorphism analysis was carried out, and samples with abnormal band pattern were commercially sequenced.
Results : Screening of cardiac ryanodine receptor revealed an insertion of a base in the intronic region of exon-28 in a patient, leading to a creation of a cryptic splice site. Screening of plakohilin-2 for mutations revealed an abnormal band pattern in three patients. Two of them had similar abnormal band pattern for exon-3.1. Sequencing revealed a novel 2 base pair deletion (433_434 delCT), which would lead to premature truncation of the protein (L145EfsX8). Another patient showed abnormal band pattern for exon-3.2 and sequencing revealed a missense mutation C792T leading to amino acid change P244L, in N-terminal, and this substitution may cause disturbances in the various protein-protein interactions.
Conclusion : This study reports novel cardiac ryanodine receptor (RyR-2) mutations and Pkp-2 for the first time from Indian population.

Keywords
Arrhythmogenic right ventricular cardiomyopathy, fibro-fatty tissue, palpitations, sudden death